The present invention relates to compounds having antitumor activity. The invention also relates to pharmaceutical compositions that contain one or more of those compounds, methods of using the compounds to inhibit tumor growth in mammals, and methods of preparing the compounds.
Many thousands of people are diagnosed with cancer each year, and although great advances have been made in cancer therapy, the existing treatments are not successful in many cases. Among the problems with existing therapies are (1) anticancer drugs administered to patients often have toxic effects on non-cancerous cells in the patient's body, (2) cancerous cells whose growth can be inhibited by certain drugs sometimes become resistant to those drugs, and (3) some cancers cannot be effectively treated with a single drug, and sometimes not even with a combination of different anticancer drugs. A long-standing need exists for new anticancer drugs that have one or more of the following characteristics: (1) ability to inhibit the growth of cancerous cells, (2) acceptable levels of toxicity to non-cancerous cells, (3) effectiveness against cancerous cells that are resistant to other drugs, and (4) a different mechanism of action than existing drugs, so that when the new drug is used in combination with an existing drug, the likelihood of the cancer cells developing cross-resistance is reduced.